Enhancement of the Magnetic Refrigerant Capacity in Partially Amorphous Fe 70Zr 30 Powders Obtained by Mechanical Alloying

Description

After mechanical alloying Fe 70Zr 30 composition from pure starting powders, an amorphous phase with Curie temperature T C = 244 K and an intermetallic compound (that should be non-stoichiometric Zr-rich fcc Fe 2Zr phase) with T C = 355 K are formed. Residual α-Fe crystallites are also found. The multiphase character of this system yields a non-monotonic dependence of the magnetocaloric effect (characterized by the refrigerant capacity, RC) on the fraction of phases. Among the samples studied in this work, RC is enhanced for samples with the highest fraction of intermetallic compound, although the maximum magnetic entropy change monotonically decreases with the increase of the fraction of this phase. This behaviour agrees with the predicted one for biphasic systems.

Abstract

Ministerio de Ciencia e Innovación MAT 2010-20537

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European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER) MAT 2010-20537

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Junta de Andalucía P10-FQM-6462

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Office of Naval Research N00014-11-1-0311

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